Synchronizing windshield wipers
AssigneeUnited Technologies Motor Systems, Inc.
InventorDavid W. Welch
Life of this patent
Estimating the term…
Abstract
Two windshield wiper blades are powered by separate electric motors. The blades overlap and when one blade is at its reversal point the other blade leaves part as the other blade begins to return to park. The position of the blades is encoded. The blades, if synchronized should be at identical locations and position codes at the same time. Motor power to the blade that arrives first is be removed, allowing the blade to coast. If the other blade still does not arrive at the position after an elapsed time, the first to arrive blade is dynamically braked. Intermittent wiper operation is provided in a way that initiates an immediate wipe if wiper delay is changed while the blades are parked.
Claims11
A windshield wiper system comprising a first wiper blade, a first motor for operating the first wiper blade, a second wiper blade, a second motor for operating the second wiper blade, characterized by:
- a first drive for providing operating power to the first motor in response to a first motor drive signal;
- a second drive for providing operating power to the second motor in response to a second motor drive signal;
- first encoder means for providing a first position signal indicating the position of the first blade;
- second encoder means for providing a second position signal indicating the position of the second blade;
- signal processing means for providing the first and second motor drive signals;
- for receiving the first and second position signals;
- for providing a coast signal if the first blade has reached a first location before the second blade has reacahed a second location;
- for interrupting the first motor drive signal in response to the coast signal;
- for providing a dynamic braking signal if the second blade has not reached the first position after a selected elapsed time following the coast signal;
- and
- first dynamic braking means responsive to the dynamic braking signal for dynamically braking the first motor.
A windshield wiper system comprising first and second wiper blades, each powered by a separate electric motor, characterized by:
- a position encoder associated with each blade for providing a signal that indicates the blade position;
- signal processing means for receiving said position signals while the first and second blades are moving and synchronizing the motion of the blades by interrupting power to a motor powering the first blade if the second blade is not at the same position as the first blade;
- dynamically braking said motor if the second blade is not at the same position as the first blade after the power is removed from said motor;
- and restoring power to said motor when the second blade is at the same position as the first blade, said positions being defined by a code provided by the encoders, the code defining wipe regions.
Dependencies are inferred from the claim text.